Grinding Wheel Research Articles

Crack characteristics of pulsed laser brazed diamond grinding wheel

Experiments on pulsed laser brazing of diamond grinding wheels were carried out in this paper. The crack characteristics and residual stress of brazed layer were detected and evaluated. The influence laws of pulse width, frequency, diamond mixing ratio, number of stacked layers, powder thickness and preheating temperature on crack characteristics were investigated. The pulsed laser characteristic coefficients (peak pulse power density/pulse interval time) and the correlation law between thermal stresses and cracks are discussed. The results show that the pulse width and frequency of the pulsed laser affect the cracking rate by varying the energy input and the time between pulses. The existence of a suitable value for the pulse characteristic coefficient corresponding to pulse width and frequency corresponds to a lower cracking rate. Thermal stress variations due to changes in process conditions at different diamond percentages, number of stacked layers, and preheating temperatures are the main causes of crack rate variations. Cracking is not only affected by thermal stresses, but also by the quality of the formed surface when pulsed laser brazing diamond to nickel–chromium alloy brazing material. For example, the main reason for the variation in cracking rate is the change in the morphology of the molded surface due to the variation in the thickness of the powder spread at different variations in the thickness of the powder spread.

Influence of dimensional deviation and thickness non-uniformity on the small-size specimen tensile results of CLF-1 steel

Tensile testing of small-size specimens has been widely used to evaluate the influence of neutron irradiation on the mechanical properties for structural materials of fusion reactors. In recent years, researchers have been trying to standardize small-size specimen tensile test method. In the present paper, we have investigated the influence of dimensional deviation and thickness non-uniformity on the tensile results of small-size specimen by both experiments and finite element simulations, based on one of the candidate structural materials of fusion reactor, i.e. CLF-1 steel. It was found that under the conditions of small grain size, small metallurgical defect size and suitable specimen preparation, the tensile results of SS-J3 specimen could be close to the results of large-size specimen. Slightly higher yield and ultimate strengths for small specimens may be caused by the surface treatment of the wheel grinding. The repeatability of ultimate strength was better than that of yield strength, and the repeatability of elongation was worse than that of strength. For tensile tests on eight SS-J3 specimens, the maximum difference in total elongation was about 3 %. With ±0.1 mm deviation of thickness and parallel width, the maximum variation in total elongation was about 1.8 %. The ductility properties were sensitive to specimen's thickness non-uniformity, the measured uniform and total elongations would obviously decrease even with 0.01 mm thickness non-uniformity.

Simulation modeling of wafer grinding surface roughness considering grinding vibration

When using the workpiece rotation method to grind wafers, the grinding end vibration will deteriorate the surface roughness of the wafers. To study the impact law of vibration on the surface roughness of wafers during the grinding procedure, this paper presents a new approach to simulate and model the surface roughness of wafer grinding considering the grinding vibration. Firstly, the dynamics model under the consideration of grinding force was established for the grinding end of the grinding wheel and workpiece turntable. Secondly, using the iterative method to solve the dynamic equations that have been established, the vibration equation is obtained by fitting the displacement vibration curve of the end. Then, by reconstructing the surface grain of the gear teeth, a simulation model of wafer grinding surface roughness was established considering material removal, grain motion and grinding vibration. And then the grinding comparison test was conducted to compare the simulation and test surface roughness measurement results. The maximum deviation of the surface roughness Sz and Sa was 7.7 % and 5.4 %, respectively. The results indicate the accuracy of the modeling. Finally, based on the established wafer roughness model, explore the impact of vibration on wafer roughness during the grinding procedure. This model provides a reference for the research of wafer precision grinding technology.

Research on On-Line Monitoring of Grinding Wheel Wear Based on Multi-Sensor Fusion.

The state of a grinding wheel directly affects the surface quality of the workpiece. The monitoring of grinding wheel wear state can allow one to efficiently identify grinding wheel wear information and to timely and effectively trim the grinding wheel. At present, on-line monitoring technology using specific sensor signals can detect abnormal grinding wheel wear in a timely manner. However, due to the non-linearity and complexity of the grinding wheel wear process, as well as the interference and noise of the sensor signal, the accuracy and reliability of on-line monitoring technology still need to be improved. In this paper, an intelligent monitoring system based on multi-sensor fusion is established, and this system can be used for precise grinding wheel wear monitoring. The proposed system focuses on titanium alloy, a typical difficult-to-process aerospace material, and addresses the issue of low on-line monitoring accuracy found in traditional single-sensor systems. Additionally, a multi-eigenvalue fusion algorithm based on an improved support vector machine (SVM) is proposed. In this study, the mean square value of the wavelet packet decomposition coefficient of the acoustic emission signal, the grinding force ratio of the force signal, and the effective value of the vibration signal were taken as inputs for the improved support vector machine, and the recognition strategy was adjusted using the entropy weight evaluation method. A high-precision grinding machine was used to carry out multiple sets of grinding wheel wear experiments. After being processed by the multi-sensor integrated precision grinding wheel wear intelligent monitoring system, the collected signals can accurately reflect the grinding wheel wear state, and the monitoring accuracy can reach more than 92%.

A study of diamond grinding wheel wear condition monitoring based on acoustic emission signals

A study of diamond grinding wheel wear condition monitoring based on acoustic emission signals

Investigating a novel and highly efficient approach for the fabrication of diamond profile rollers using Wire Electrical Discharge Conditioning (WEDC)

The fabrication of high-precision and high-performance profile rollers represents the main challenge of utilizing profile rollers as dressers to condition conventional grinding wheels. This results in high demands for an efficient process to manufacture profile rollers (form dressing wheels). Conventionally, diamond profile rollers have been produced through infiltration or negative electroplating methods. Nevertheless, these manufacturing methods suffer significant drawbacks, including extended production times and substantial costs. This study presents an innovative approach to fabricating diamond profile rollers using Wire Electrical Discharge Conditioning (WEDC). The WED-Conditioning emerges as an effective alternative to profile metal-bonded rotary diamond dressing tools. This innovative method leads to the production of diamond profile rollers in significantly shorter timeframes and at a more economical cost compared to the conventional manufacturing method with comparable quality. The research delves into the influence of profile roller specifications and conditioning strategies on the achievable profile accuracy and topography of the profile rollers. Also, the wear behavior of the WEDC-conditioned profile roller over long-term conditioning of conventional grinding wheels was studied. The findings highlight the significant contribution of the appropriate selection of WEDC strategies to the profile accuracy, with the potential to achieve profile accuracies comparable with conventional profile rollers. As well, grain size emerges as the primary determinant of achievable profile accuracy for profile rollers. The findings of this study could provide insights into optimizing the manufacturing process for super abrasive diamond profile rollers, thereby enabling their widespread use in the grinding industry.

The Process Optimization Analysis of CBN Abrasive Cu-Sn-Ti Coating Fabrication via the Ultrasonic-Vibration-Assisted Laser Cladding Method

Ultra-precision machining has higher requirements for the performance of abrasive tools, but the traditional grinding wheel has some problems such as irregular grain arrangement, limited chip space, and high grinding temperature. Therefore, a structured grinding wheel suitable for ultra-precision machining is proposed. In this study, the laser cladding method and ultrasonic vibration technology were combined to study the preparation process of a structured grinding wheel. Firstly, the quality evaluation system of the printing layer was established, and the shape coefficient and dilution rate were used to evaluate the laser cladding quality. The effects of laser power, sweep speed, powder feeding speed, and ultrasonic power on the shape coefficient and dilution rate of the printing layer were analyzed by single-factor experiments. The level range of each factor in the orthogonal experiment was established to optimize the process parameters. The surface morphology was observed, and the influence of ultrasonic vibration on the morphology was analyzed. The structured grinding wheel was prepared according to the optimized parameters.

Experimental study on grinding process of Al-Mg2Si aluminum matrix composites

As an aluminum-based reinforcement, Mg2Si particles have excellent properties such as high hardness, high melting point, and high elastic modulus compared with other reinforcements and are widely used in aerospace and automobile fields. However, there is little research on the cutting mechanism of this material. In order to explore the surface grinding mechanism of Mg2Si/Al composites, Grinding simulation of low-volume fraction Mg2Si/Al composites was carried out by ABAQUS, and the influence of different positions of matrix and particle removal on the surface quality of Mg2Si/Al composites was expounded. The plane reverse grinding test was carried out by using CBN (boron nitride) grinding wheel. The L16(43) orthogonal test and three groups of single factor tests were designed. The orthogonal results show that the linear velocity of the grinding wheel has the greatest influence on the surface roughness, and the feed rate and grinding depth are significantly smaller. The range analysis shows that the optimal grinding parameters are: vs = 35 m/s, vw = 0.75 m/min, ap = 0.015 mm. The regression equation for surface roughness was established by using MATLAB. The single factor results show that the surface quality is obviously improved by increasing the linear velocity of the grinding wheel and reducing the feed rate and grinding depth through the observation of the morphology of the processed specimen. The analysis results show that defects such as pits, protrusions, burrs, and a small amount of fish-scale-like on the machined surface are mainly caused by the linear velocity of the grinding wheel, the pulling force of the grinding wheel, and the adhesion of the debris. The defects such as particle micro-cracks, particle pull-out, and matrix cracking on the subsurface, are mainly caused by the compressive stress of the grinding wheel and the stress concentration of the particles. The research results have guiding significance for future composite material cutting research and actual cutting processing.

MECHANICAL CHARACTERIZATION OF RUBBER-BONDED ELASTIC GRINDING WHEELS BY BENDING TESTS

The elastic modulus of a grinding wheel is one of the most representative properties when it comes to the study of its in process behavior, which makes it a parameter of great interest for both researchers and manufacturers of grinding wheels. Rubber-bonded grinding wheels are characterized by their high elasticity, which makes them stand out in superfinishing applications, achieving surface roughness of Rz < 1 µm and mitigating the risk of burning the ground parts. Despite the good performance of this type of grinding wheel, they are not as popular as conventional rigid wheels, and their mechanical characteristics are still unknown. Moreover, while a few investigations have focused on determining the mechanical properties and their relationship with the in-process performance of vitrified or resinoid bonded grinding wheels, there are not investigations that have studied the mechanical properties of elastic grinding wheels. In this work, the elastic modulus, flexural strength and deformation of rubber-bonded elastic grinding wheels have been studied by means of three-point bending tests. Different compositions of the different materials that make up this type of grinding wheel have been analyzed, as well as the strength of the bond between the abrasive compound and the grinding wheel core. This study is intended to help to better understand the behavior of elastic grinding wheels and to develop more efficient grinding processes. In addition, it allows manufacturers to increase their knowledge of the properties of this type of grinding wheel and offers an effective method for its mechanical characterization. Keywords: Grinding, elastic grinding wheels, rubber bond, wheel characterization, elastic modulus, flexural strength, bending

Исследование параметров системы аспирации рельсошлифовального поезда

The rail-grinding technology is used for the railway network of the JSC RZhD to eliminate rail defects and extend the lifecycle of the railway track. In order to implement the rail-grinding technology, currently, rail-grinding trains RShP-48 are used. Rails are ground with special grinding wheels made of zirconium electro-corundum manufactured based on aluminum oxide and zirconium oxide, with bakelite organic bond as a binder. In addition, the abrasive wheel composition includes various chemical components. When an abrasive tool is destructed, grinding waste in the form of suspensions is generated during its mechanic work. The suspensions spread over long distances and negatively affect both the environment and the working conditions of the rail-grinding train maintenance personnel. Today, the company «Sinara — Transport Machines» is developing a new rail-grinding train RShP 2.0 with a pre-installed aspiration system to collect grinding wastes for further utilization. When developing the technical design of RShP 2.0, the main characteristics of the aspiration system have been determined. In order to confirm the efficiency of the obtained parameters of the aspiration system, laboratory tests have been conducted on a special rail-grinding unit. According to the results, the aspiration system with the stated technical characteristics absorbs the fine fraction of grinding products which is about 50 % of the total lost mass of the grinding wheel. Considering a large abrasive that sticks to the spark arrestors together with metal chips, the aspiration system RShP 2.0 will enable removing up to 90 % of grinding waste.

Influence of Additives on Grinding Performance of Digital Light Processing-Printed Phenol Bond Grinding Wheels

Resin bond grinding wheels are the most common grinding tools in the industry. Until now, all research on the additive manufacturing of resin bond grinding wheels has focused on commercially available acrylate resin. However, using a phenol-based bond to print resin-bond grinding wheels has been challenging for researchers and industries. In this study, a photo-curable phenol resin bond grinding wheel was introduced for the first time, offering advantages such as lower cost, high thermal resistance, and good mechanical properties. To enhance the grinding performance of the printed wheels, various additives, such as copper, glass fiber, and carbon fiber, were incorporated into the composition. Different on-machine and out-of-machine measurements, such as force, tool wear, dimensional accuracy, and optical microscopy measurements, were conducted to investigate the grinding performance of the printed wheels. The results demonstrate that printed grinding wheels have strong potential in grinding applications, which was more prominent for the bond reinforced by glass fibers, providing improved mechanical properties (up to 50%), wear resistance (up to 75%), and higher dimensional accuracy (up to 11%).

A Study on the Analysis of Machining Characteristics and Derivation of Optimal Machining Conditions of Grinding Wheel for Gear Grinding

A Study on the Analysis of Machining Characteristics and Derivation of Optimal Machining Conditions of Grinding Wheel for Gear Grinding

Research on Cloud-Edge-Device Collaborative Intelligent Monitoring System of Grinding Wheel Wear State for High-Speed Cylindrical Grinding of Bearing Rings

Aiming at the problems of grinding wheel wear during high-speed cylindrical grinding, communication delays, and slow response during data acquisition, processing, and system operation, an intelligent online monitoring technology frame for CNC manufacturing units is proposed, incorporating a real-time-perception grinding mechanism and a cloud-edge device. Based on the grinding data and grinding wheel wear mechanism, a monitoring model using multi-sensor information fusion is constructed to assess the grinding wheel wear state. In addition, edge data acquisition and online monitoring software have been developed to improve the speed of data transmission and processing. Finally, based on the proposed framework, a cloud-edge device collaborative intelligent monitoring system for assessing grinding wheel wear during high-speed cylindrical grinding of bearing rings is constructed. It improves the grinding quality and efficiency, reduces the grinding cost, and incorporates remote control functionality.

Topography Modeling of Surface Grinding Based on Random Abrasives and Performance Evaluation

The surface morphology and roughness of a workpiece are crucial parameters in grinding processes. Accurate prediction of these parameters is essential for maintaining the workpiece’s surface integrity. However, the randomness of abrasive grain shapes and workpiece surface formation behaviors poses significant challenges, and accuracy in current physical mechanism-based predictive models is needed. To address this problem, by using the random plane method and accounting for the random morphology and distribution of abrasive grains, this paper proposes a novel method to model CBN grinding wheels and predict workpiece surface roughness. First, a kinematic model of a single abrasive grain is developed to accurately capture the three-dimensional morphology of the grinding wheel. Next, by formulating an elastic deformation and formation model of the workpiece surface based on Hertz theory, the variation in grinding arc length at different grinding depths is revealed. Subsequently, a predictive model for the surface morphology of the workpiece ground by a single abrasive grain is devised. This model integrates the normal distribution model of abrasive grain size and the spatial distribution model of abrasive grain positions, to elucidate how the circumferential and axial distribution of abrasive grains influences workpiece surface formation. Lastly, by integrating the dynamic effective abrasive grain model, a predictive model for the surface morphology and roughness of the grinding wheel is established. To examine the impact of changing the grit size of the grinding wheel and grinding depth on workpiece surface roughness, and to validate the accuracy of the model, experiments are conducted. Results indicate that the predicted three-dimensional morphology of the grinding wheel and workpiece surfaces closely matches the actual grinding wheel and ground workpiece surfaces, with surface roughness prediction deviations as small as 2.3%.

Rapid Assessment of Steel Machinability through Spark Analysis and Data-Mining Techniques

The machinability of steel is a crucial factor in manufacturing, influencing tool life, cutting forces, surface finish, and production costs. Traditional machinability assessments are labor-intensive and costly. This study presents a novel methodology to rapidly determine steel machinability using spark testing and convolutional neural networks (CNNs). We evaluated 45 steel samples, including various low-alloy and high-alloy steels, with most samples being calcium steels known for their superior machinability. Grinding experiments were conducted using a CNC machine with a ceramic grinding wheel under controlled conditions to ensure a constant cutting force. Spark images captured during grinding were analyzed using CNN models with the ResNet18 architecture to predict V15 values, which were measured using the standard ISO 3685 test. Our results demonstrate that the created prediction models achieved a mean absolute percentage error (MAPE) of 12.88%. While some samples exhibited high MAPE values, the method overall provided accurate machinability predictions. Compared to the standard ISO test, which takes several hours to complete, our method is significantly faster, taking only a few minutes. This study highlights the potential for a cost-effective and time-efficient alternative testing method, thereby supporting improved manufacturing processes.

HYPREZ Wafering Solutions: A Novel Approach of SiC Wafering Solution

A novel approach for processing SiC wafers has been developed to grind then polish 150 and 200mm SiC wafers without lapping. The purpose of this work was to optimize the processing of SiC wafers sliced from boules to finished epi-ready wafers by grinding and chemical-mechanical polishing (CMP). Diamond vitrified wheels were used for coarse and fine grinding to correct the irregular shape of SiC wafers before reducing surface roughness by CMP. 4H-SiC wafers were sliced by diamond embedded/slurry wire saw and laser split techniques. Incoming wafer condition was seen to affect coarse grinding wheel performance depending on incoming surface roughness and shape. Wheel characteristics, including abrasive size, abrasive concentration, and bond structure, were adjusted to improve grinding efficiency based on incoming conditions. Coarse grinding wheels were able to reduce wafer total thickness variation to 3-5um and average surface roughness to 20-30nm (Ra). Fine grinding wheels were optimized to reduce total thickness variation (TTV) below 2um and surface roughness to 1-2nm Ra and peak-to-valley height of 20-30nm (Rt). Coarse and fine wafering time was less than 30 minutes total to remove 50 microns on both Si and C-face per wafer. Surface damage from grinding was removed after one hour of polishing each wafer by CMP, achieving surface roughness of 0.4nm Ra and 5-7nm Rt. The benefit of optimizing coarse and fine grinding of 150 and 200mm SiC wafers is demonstrated by producing flat wafers, which reduced overall processing time to prepare an epi-ready condition by CMP.

Laser dressing process monitoring of superabrasive grinding wheel based on spectroscopy

In order to solve the problems of poor efficiency and low automation in laser dressing of superabrasive grinding wheels, the spectral monitoring research based on the automatic dressing of superabrasive grinding wheels was systematically carried out in this paper. For the first time, the characteristic element spectral lines that could respectively characterize the identity information of grain and bond were established, and by monitoring the characteristic element spectral line waveforms, the profiling/sharpening processing status identification was realized. It was the first to propose using the presence or absence of line spectrum during the laser dressing process as a monitoring indicator, which could achieve qualitative identification of the high-efficiency processing status of the laser beam focus. When the laser beam was in the positive defocus state, the material could be removed more accurately. A greater quantity of material would be eliminated when the laser beam was in the negative defocus state. The mapping relationship between the spectral characteristic waveform and the defocus amount of the laser beam during the laser dressing process was revealed, and a spectral monitoring theory of the defocus amount fluctuation of superabrasive grinding wheels was constructed. A high-efficiency automated laser profiling method for grinding wheels based on spectrum-assisted monitoring and self-adaptive feed was innovatively explored, and experiments had proven that this method could achieve self-adaptive feed for laser beam fast slow compensation, ultimately achieving high efficiency and automatic dressing of superabrasive grinding wheels.

Investigation into the role of Si and SiC phases in RB-SiC ceramics surface modified ultra-precision grinding

RB-SiC ceramic has greater specific stiffness and thermal stability as space optical materials in the field of deep space exploration. To ultra-precision grinding advanced manufacturing technology drawbacks, a fabrication of highly shape accuracy and surface quality and surface modification assisted processing at room temperature. The RB-SiC ceramics are modified by plasma torches to produce compounds with lower hardness values, an exceptional surface quality (Sa surface roughness of [0.481, 0.959]), and has excellent thermal and chemical stability after surface modification process via 100 °C plasma torch at room temperature environment, which makes it an ideal suitable for the deep space exploration conditions such as space optical materials. In addition, oxygen(O2) plasma surface modification and finite element simulation force-heat conduction of RB-SiC ceramic hard-brittle materials surface grinding force were compared with advanced manufacturing experiments of the precision grinding, revealing the formation mechanism and influence mechanism of surface micro-morphology during micro-cutting of precision grinding finish surface. The advanced manufacturing precision grinding difficulties of RB-SiC ceramic oxygen plasma torch reducing subsurface damage and removing space optical hard-brittle materials via ultra-precision grinding process of resin-funded corundum grinding wheel were solved. Subsurface damage (SSD) was effectively inhibited and its formation mechanism model.

Pressure Distribution and Wear of Grinding Wheel in Ultra-Thinning Process of LiTaO3 Wafer

Pressure Distribution and Wear of Grinding Wheel in Ultra-Thinning Process of LiTaO3 Wafer

Optimal design and performance evaluation of grinding wheels with triply periodic minimal surface lattice structure

High-performance grinding wheels are critical tools for precision surface generation. In precision grinding processes, the coolant supply at the wheel-workpiece interface is critical for reducing grinding temperature and detrimental friction. For better lubrication and chip removal performance, the cavities or pores need to be generated throughout the grinding wheel. The ideal morphology of pores in grinding wheels should be inter-connected and capable of providing sufficient coolant. Conventional grinding wheel design and fabrication methods can only passively generate closed circular pores by using pore-forming agents. Increasing the percentage of pores in this way generally leads to an uncontrollable reduction in mechanical strength, while the closed pores are insufficient in cooling performance. In this paper, the grinding wheels with triply periodic minimal surface lattice structure are designed and fabricated, which achieves the regulable and inter-connected internal structure of grinding wheels. Meanwhile, to balance the relationship between the structural properties and performance indicators of porous grinding wheels, an optimal design method for the porous structure of grinding wheels is proposed. Finally, the grinding performance of the novel grinding wheels in comparison to electroplated diamond grinding wheels is investigated in terms of grinding force, specific grinding energy and ground surface roughness.